Make sure data in transmit buffer gets transmitted as soon as possible.

diff --git a/od-win32/serial_win32.cpp b/od-win32/serial_win32.cpp
index b7e90a79a62db977e7f08e6421f1fa5805440a70..40d168d02eb0727b7994df4166274371c121c829 100644 (file)
--- a/od-win32/serial_win32.cpp
+++ b/od-win32/serial_win32.cpp
@@ -380,18 +380,31 @@ static void checksend(void)
                serial_send_previous = serdatshift_masked;
        }
 #endif
-       data_in_sershift = 2;
+       if (serial_period_hsyncs <= 1) {
+               data_in_sershift = 0;
+               serdatcopy();
+       } else {
+               data_in_sershift = 2;
+       }
 #if SERIALDEBUG > 2
        write_log(_T("SERIAL: send %04X (%c)\n"), serdatshift, dochar(serdatshift));
 #endif
 }
 
-static void sersend_ce(uae_u32 v)
+static bool checkshiftempty(void)
 {
        checksend();
        if (data_in_sershift == 2) {
                data_in_sershift = 0;
                serdatcopy();
+               return true;
+       }
+       return false;
+}
+
+static void sersend_ce(uae_u32 v)
+{
+       if (checkshiftempty()) {
                lastbitcycle = get_cycles() + ((serper & 0x7fff) + 1) * CYCLE_UNIT;
                lastbitcycle_active_hsyncs = ((serper & 0x7fff) + 1) / maxhpos + 2;
        } else if (data_in_sershift == 1) {
@@ -489,18 +502,16 @@ void serial_hsynchandler (void)
        if (serial_period_hsyncs == 1 || (serial_period_hsync_counter % (serial_period_hsyncs - 1)) == 0) {
                checkreceive_serial();
                checkreceive_enet();
-       }
-       if ((serial_period_hsync_counter % serial_period_hsyncs) == 0 && !currprefs.cpu_cycle_exact) {
-               checksend();
-               if (data_in_sershift == 2) {
-                       data_in_sershift = 0;
-                       serdatcopy();
-               }
+               checkshiftempty();
+       } else if ((serial_period_hsync_counter % serial_period_hsyncs) == 0 && !currprefs.cpu_cycle_exact) {
+               checkshiftempty();
        }
 }
 
 void SERDAT (uae_u16 w)
 {
+       serdatcopy();
+
        serdat = w;
 
        if (!w) {